In the field of rolling, the need to correctly direct the metal product entering between the work rolls of a rolling stand is known.
This need is even more urgent in the case of rolling long products such as bars, metal wire or other, in which the work rolls are shaped in a coordinate and complementary way to the section of the rolled product.
Generally, to guarantee the centering of the rolled product with respect to the rolling channel defined by the work rolls, it is known to provide guide rollers, disposed upstream of the rolling stand, with respect to the advance of the metal product.
Such guide rollers are disposed opposite each other with respect to a nominal rolling axis, and tend to maintain the metal product along this axis, as it enters between the work rolls.
Solutions are also known in which the position of the guide rollers is adjustable, with respect to the rolling axis, depending on the dimensions of the metal product, and/or possible variations in the operating conditions.
It is known to move each guide roller independently by means of a specific actuator.
This known solution has considerable disadvantages in the coordination of the actuators, with greater inaccuracies of positioning and centering of the metal product with respect to the work rolls and to the rolling axis.
It is also known to connect the guide rollers in pairs or threes on one side or the other with respect to the rolling axis, so as to provide a common actuator for each pair or threesome.
However, this known solution, as well as having disadvantages connected to the coordination of the actuators, in any case does not guarantee a sufficiently accurate centering of the metal product with respect to the rolling axis, since it has to provide independent feeds for the actuators.
Solutions in which the guide rollers are assembled movable with respect to a body are also known, as in European patent EP-B-0143523, in which they are simultaneously movable by means of a common adjustment mechanism, in a direction inclined with respect to the rolling axis.
In this type of known solution, the movement of the rolling rolls, which occurs in an inclined direction with respect to the axis, is not easily controllable and predictable, in that the final position of the guide rollers depends, on each occasion, on different geometric factors, among which the angle of movement, the actual size of the metal product and others.
This solution is thus difficult to operate and manage, and has high manufacturing costs due mainly to the need to provide inclined guides or conical parts mating with each other, with complex actuation mechanisms.
Moreover, some of the known solutions provide the need to temporarily disassemble the adjustment device with respect to the rolling line, to carry out the adjustment of the reciprocal position of the guide rollers. This known operating mode entails long equipping times and possible inaccuracies in the in line re-positioning of the adjustment device.
One purpose of the present invention is to achieve an adjustment device for guide rollers which is both simple and economical, which is easy to manage, and which allows to obtain an efficient and precise adjustment, guaranteeing the correct centered positioning of the metal product with respect to the rolling channel defined by the work rolls.
Another purpose of the present invention is to achieve an adjustment device for guide rollers which allows to carry out the adjustment of the position of the guide rollers even keeping the device in line on the adjustment plant.
Another purpose of the present invention is to perfect a method which allows an efficient and precise adjustment, guaranteeing the correct centered positioning of the metal product with respect to the work rolls.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.